Question 1

What is ICD-10 code O30.031?

Accepted Answer

O30.031 is the ICD-10-CM diagnosis code for twin pregnancy, monochorionic/diamniotic, first trimester. A pregnancy with two babies sharing one placenta but each in their own amniotic sac during the first three months of pregnancy. O30.031 sits in the ICD-10-CM chapter for pregnancy, childbirth and the puerperium (o00-o9a), within the section covering maternal care related to the fetus and amniotic cavity and possible delivery problems (o30-o48).

O30.031 is a billable ICD-10-CM code but does not map to a payment HCC under the CMS-HCC V28, V24, ESRD, or RxHCC risk adjustment models. It can be reported on Medicare Advantage encounter data submissions but it does not contribute to a beneficiary's RAF score and therefore does not affect risk-adjusted payments to the plan.

Monochorionic/diamniotic twins have one shared placenta (mono) but separate amniotic sacs (di), which carries specific risks that should be documented.

Question 2

Is O30.031 an HCC code?

Accepted Answer

No. O30.031 is a billable ICD-10-CM code but does not map to any payment HCC category under the CMS-HCC V28, V24, ESRD, or RxHCC risk adjustment models. It can still be reported on Medicare Advantage encounter data submissions, but it does not contribute to the beneficiary's Risk Adjustment Factor (RAF) score and therefore does not affect the risk-adjusted capitation payment to the plan. V28 reached 100% phase-in for payment year 2026.

Question 3

Is O30.031 billable?

Accepted Answer

Yes. O30.031 is a billable ICD-10-CM code that can be reported on professional and institutional claims as a primary or secondary diagnosis when the provider documentation supports the specific condition described. Billable codes in ICD-10-CM are coded to the highest level of specificity available for the documented diagnosis. O30.031 is current for fiscal year 2026 and remains in the active CMS ICD-10-CM code set published by the National Center for Health Statistics.

Question 4

What is the V28 vs V24 difference for O30.031?

Accepted Answer

O30.031 does not map to a payment HCC under either the CMS-HCC V28 risk adjustment model or the older V24 model. V28 reached 100% phase-in for payment year 2026, replacing V24 which was used during the PY2024–PY2025 transition. Because neither model rewards O30.031 with a risk adjustment factor, it contributes zero to a Medicare Advantage beneficiary's RAF score in either version. Coders should check whether provider documentation supports a more specific child code that does map to a payment HCC.

Question 5

What should coders know when reporting O30.031?

Accepted Answer

Monochorionic/diamniotic twins have one shared placenta (mono) but separate amniotic sacs (di), which carries specific risks that should be documented The trimester specification is required; use first trimester (weeks 1-13) for this code

O30.031

Is O30.031 an HCC code?

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Open O30.031 in the Interactive Encoder